Depressants

Depressants are substances that [diminish] the activity of the central nervous
system.

Depressants are often referred to as "downers" because of their sedative,
hypnotic, and tranquilizing effects.

There are both legal and illegal depressants. Alcohol is the most common legal
depressant. Other depressants that are legal are often prescribed medications
used to induce sleep, relieve stress, and subdue anxiety.